Spatio-environmental determinants of the genetic structure of three steppe species in a highly fragmented landscape

All three species are long-lived, which may contribute to explaining why genetic effects of recent fragmentation are still limited. We highlight that floristic composition can be a powerful predictor of population differentiation in species that show rather stable conditions in their recent population histories (e.g. A. villosa). This can have important implications for identifying source populations where restoration actions involve the (re)introduction of propagules. In contrast, for P. hybrida and J. multiflora, we could not identify deterministic drivers of differentiation. We advocate that future studies should aim at disentangling the interactive effects of varying life cycles, eco-evolutionary population histories and spatio-environmental heterogeneity in fragmented landscapes.